Weight loss in chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and may negatively affect bone mineral density. Increased serum levels of cytokines such as tumour necrosis factor (TNF)-alpha have been associated with weight loss and with bone resorption. We studied the association between systemic inflammation, markers for bone turnover and recent weight change in underweight (n=48) and normal-weight patients (n=23) candidates for lung transplantation where the majority (56%) had COPD. Osteoporosis or osteopenia was present in all the diagnostic groups. The resulting model of linear regression in COPD patients showed that for the 1-CTP (a marker of bone resorption) model, the total variation of 61% was explained by recent weight change, sTNF-alpha receptor(R)II, dose of prednisolon and age. The resulting model of linear regression in the whole group of patients showed that the total variation of 72% was explained by recent weight change, sTNF-alpha RI, diagnosis (COPD/other diagnosis), dose of prednisolon and C-reactive protein. In conclusion, our results showed that serum concentration of 1-CTP was positively associated with sTNF-alpha receptor II and negatively with recent weight change in patients with advanced COPD. Recent weight loss in both the underweight and normal-weight patients showed to be a more important contributor than recent weight loss only in underweight patients for explaining variations in 1-CTP.